蒸汽发生器传热管电涡流检测探头响应的理论建模与仿真

为了研究蒸汽发生器传热管缺陷与探头信号的定量关系以实现缺陷的自动定量检测,利用有限元方法建立了蒸汽发生器传热管电涡流检测探头响应的理论模型。通过仿真和实验研究环形槽和腐蚀坑两种典型缺陷的探头响应信号,发现仿真与实验结果的规律一致,验证了所建模型的正确性。随后,应用本文所建理论模型仿真研究了缺陷位置和大小对探头信号的影响规律。结果表明:在优化工作频率的前提下,内壁缺陷和外壁缺陷的信号相位差异显著,探头信号的强弱主要取决于缺陷大小。据此,可根据探头信号的相位识别缺陷位置,根据探头信号的大小量化缺陷参数。该研究成果可为蒸汽发生器传热管电涡流检测探头信号的自动分析提供理论依据。

Modeling and simulation of probe response for eddy current testing of steam generator tubes

In order to investigate the quantitative relationship between signals from the probe and defects in heat transfer tubes in steam generator （SG）, so as to achieve quantitative automatic inspection, a theoretical model is established for probe response to the eddy currents in SG tubes by finite element method. Then, simulations and experiments are carried out to study the signals from the typical defects of circular grooves and corrosion pit. It is found that numerical results are consistent with experimental data, which verify the accuracy of this model. Subsequently, with the established model, the influence of positions and sizes of the defects on the probe signal is investigated. It is shown that phase shift is dramatic between the signals in the inner surfaces and those in the outer surfaces under optimal excitation frequency, and amplitude of probe signals mainly depend on the size of de- fects. Therefore, the positions of defects can be identified through the phases of probe signals, and the sizes of defects can be i- dentified through the amplitudes of probe signals. These results can provide theoretical basis for the automatic analysis of probe signals from eddy currents in heat transfer tubes in steam generators.